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mtd: nand: denali: remove unneeded find_valid_banks()

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The function find_valid_banks() issues the Read ID (0x90) command,
then compares the first byte (Manufacturer ID) of each bank with
the one of bank0.

This is equivalent to what nand_scan_ident() does.  The number of
chips is detected there, so this is unneeded.

What is worse for find_valid_banks() is that, if multiple chips are
connected to INTEL_CE4100 platform, it crashes the kernel by BUG().
This is what we should avoid.  This function is just harmful and
unneeded.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This commit is contained in:
Masahiro Yamada 2017-06-13 22:45:36 +09:00 committed by Boris Brezillon
parent b21ff825d6
commit 959e9f2ae9
2 changed files with 0 additions and 48 deletions
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47
drivers/mtd/nand/denali.c
View file

@ -337,51 +337,6 @@ static void get_samsung_nand_para(struct denali_nand_info *denali,
}
}
/*
* determines how many NAND chips are connected to the controller. Note for
* Intel CE4100 devices we don't support more than one device.
*/
static void find_valid_banks(struct denali_nand_info *denali)
{
uint32_t id[denali->max_banks];
int i;
denali->total_used_banks = 1;
for (i = 0; i < denali->max_banks; i++) {
index_addr(denali, MODE_11 | (i << 24) | 0, 0x90);
index_addr(denali, MODE_11 | (i << 24) | 1, 0);
index_addr_read_data(denali, MODE_11 | (i << 24) | 2, &id[i]);
dev_dbg(denali->dev,
"Return 1st ID for bank[%d]: %x\n", i, id[i]);
if (i == 0) {
if (!(id[i] & 0x0ff))
break; /* WTF? */
} else {
if ((id[i] & 0x0ff) == (id[0] & 0x0ff))
denali->total_used_banks++;
else
break;
}
}
if (denali->platform == INTEL_CE4100) {
/*
* Platform limitations of the CE4100 device limit
* users to a single chip solution for NAND.
* Multichip support is not enabled.
*/
if (denali->total_used_banks != 1) {
dev_err(denali->dev,
"Sorry, Intel CE4100 only supports a single NAND device.\n");
BUG();
}
}
dev_dbg(denali->dev,
"denali->total_used_banks: %d\n", denali->total_used_banks);
}
/*
* Use the configuration feature register to determine the maximum number of
* banks that the hardware supports.
@ -439,8 +394,6 @@ static uint16_t denali_nand_timing_set(struct denali_nand_info *denali)
ioread32(denali->flash_reg + RDWR_EN_HI_CNT),
ioread32(denali->flash_reg + CS_SETUP_CNT));
find_valid_banks(denali);
/*
* If the user specified to override the default timings
* with a specific ONFI mode, we apply those changes here.

1
drivers/mtd/nand/denali.h
View file

@ -326,7 +326,6 @@ struct denali_nand_info {
int platform;
struct nand_buf buf;
struct device *dev;
int total_used_banks;
int page;
void __iomem *flash_reg; /* Register Interface */
void __iomem *flash_mem; /* Host Data/Command Interface */